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Bizhub C759 FirmwareOperating system · Konicaminolta

CVE-2021-20872

MEDIUM · 6.8 CVSS v3.1 Published 2022-01-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
Remediation priority · Elevated
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Protection mechanism failure vulnerability in KONICA MINOLTA bizhub series (bizhub C750i G00-35 and earlier, bizhub C650i/C550i/C450i G00-B6 and earlier, bizhub C360i/C300i/C250i G00-B6 and earlier, bizhub 750i/650i/550i/450i G00-37 and earlier, bizhub 360i/300i G00-33 and earlier, bizhub C287i/C257i/C227i G00-19 and earlier, bizhub 306i/266i/246i/226i G00-B6 and earlier, bizhub C759/C659 GC7-X8 and earlier, bizhub C658/C558/C458 GC7-X8 and earlier, bizhub 958/808/758 GC7-X8 and earlier, bizhub 658e/558e/458e GC7-X8 and earlier, bizhub C287/C227 GC7-X8 and earlier, bizhub 287/227 GC7-X8 and earlier, bizhub 368e/308e GC7-X8 and earlier, bizhub C368/C308/C258 GC9-X4 and earlier, bizhub 558/458/368/308 GC9-X4 and earlier, bizhub C754e/C654e GDQ-M0 and earlier, bizhub 754e/654e GDQ-M0 and earlier, bizhub C554e/C454e GDQ-M1 and earlier, bizhub C364e/C284e/C224e GDQ-M1 and earlier, bizhub 554e/454e/364e/284e/224e GDQ-M1 and earlier, bizhub C754/C654 C554/C454 GR1-M0 and earlier, bizhub C364/C284/C224 GR1-M0 and earlier, bizhub 754/654 GR1-M0 and earlier, bizhub C3851FS/C3851/C3351 GC9-X4 and earlier, bizhub 4752/4052 GC9-X4 and earlier) allows a physical attacker to bypass the firmware integrity verification and to install malicious firmware.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This vulnerability allows a physical attacker to bypass the firmware integrity verification mechanism in Konica Minolta bizhub series printers. An attacker with physical access can install malicious firmware by circumventing the built-in verification checks, potentially gaining persistent control over the device, exfiltring print jobs, or using the compromised device as a pivot point in the network.

MitigationApply vendor-supplied firmware updates to all affected bizhub devices to patch the integrity verification bypass; additionally, restrict physical access to printers in secure locations and monitor for unauthorized physical access attempts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Bizhub C759 FirmwareOperating system
Affected:< gca-y1
Bizhub C659 FirmwareOperating system
Affected:< gca-y1
Bizhub C658 FirmwareOperating system
Affected:< gca-y1
Bizhub C558 FirmwareOperating system
Affected:< gca-y1
Bizhub C458 FirmwareOperating system
Affected:< gca-y1
Bizhub 958 FirmwareOperating system
Affected:< gca-y1
Bizhub 808 FirmwareOperating system
Affected:< gca-y1
Bizhub 758 FirmwareOperating system
Affected:< gca-y1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Physical
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the bizhub device model
    Locate the model label on the front or interior of the device, or access the device web interface or control panel to view the model information
    Affected if The model is one of: C759, C659, C658, C558, C458, 958, 808, or 758
  2. Determine the installed firmware version
    Access the device control panel or web interface and navigate to the firmware version information page, typically found under Device Information, System Information, or Maintenance settings
    Affected if The firmware version is visible and can be compared to the threshold
  3. Compare installed firmware against the affected version
    Compare the firmware version string to gca-y1 using standard version comparison
    Affected if The installed firmware version is lower than gca-y1 (for example, gca-x2, gca-w3, or any version prefix lower than gca-y1)
  4. Confirm the physical access exposure
    Evaluate whether the device is located in an area with uncontrolled physical access, such as public hallways, unlocked rooms, or areas accessible to unauthorized personnel
    Affected if The device can be accessed physically by unauthorized individuals, which is required for exploitation

The device is affected if it is a bizhub C759, C659, C658, C558, C458, 958, 808, or 758 model running firmware version lower than gca-y1 and is physically accessible to an attacker.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied firmware updates to all affected bizhub devices to patch the integrity verification bypass; additionally, restrict physical access to printers in secure locations and monitor for unauthorized physical access attempts.

Recommended fix High confidence

Firmware version gca-y1 or later for bizhub C759/C659/C658/C558/C458/958/808/758

  1. 1. Identify the specific bizhub model from the affected list (C759, C659, C658, C558, C458, 958, 808, or 758).
  2. 2. Navigate to KONICA MINOLTA's official support website (www.konicaminolta.com or www.konicaminolta.jp).
  3. 3. Locate the firmware download section for your specific bizhub model.
  4. 4. Download the firmware version gca-y1 or later for your model.
  5. 5. Follow KONICA MINOLTA's standard firmware update procedure (typically via the device's web interface or USB update feature).
  6. 6. After updating, verify that the firmware version is now gca-y1 or higher to confirm the fix is applied.
Caveat Standard firmware update risks apply - ensure stable power during update and backup device configuration if needed

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Bizhub C759 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing3.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,050
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-20872 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data